The present invention relates to resealable closure devices for storage containers and other applications.
Resealable closure assemblies have become a fixture of the storage container industry. Thermoplastic bags, in particular, have gone through several stages of closure devices.
It is known in the prior art to provide plastic bags with mating profiles, so that a bag may be sealed by applying force with the fingers to cause the profiles to mate and un sealed by applying force with the fingers to cause the profiles to disengage.
Slider assemblies are also known for achieving sealing and unsealing of suitably fitted plastic bags. Use of a slider facilitates sealing and unsealing of such plastic bags. Slider assemblies include profile strips with male and female elements working in cooperation with a slider that straddles the top of the strips. The slider serves to join the male and female elements together when drawn in one direction, and to separate the profiles when drawn in the opposite direction. Generally, the elements are forced apart, one element at a time, by a separating finger on a top inside panel of the slider.
In a first embodiment, a zipper profile for a fastener assembly includes a male element and a female element. The female element has a pair of jaws that are movable with respect to one another about a common fulcrum region. The female element also has a pair of arms each of which is coupled to a corresponding one of the pair of jaws at the fulcrum region. Each of the arms has an end opposite from the fulcrum region that is shaped for engagement with a slider. The jaws have an open position and a closed position, and the arms are disposed to cause movement of the jaws between the closed position and the open position when the arms experience displacement about the fulcrum region. Such displacement about the fulcrum region is effectuated by motion of the slider relative to the arms. The male element is captured by the female element when the jaws are in the closed position and released when the jaws are in the open position.
In accordance with another embodiment of the invention, the male element includes an end region for engagement with the slider. In a further embodiment, one of the jaws of the female element includes a first hook and the male element includes a tip having a second hook. The first and second hooks become engaged when the jaws are closed.
In another embodiment of the invention, a fastener assembly includes a first profile strip with a female element having a pair of jaws which are movable with respect to one another about a common fulcrum region. The female element of the first profile strip also includes a pair of arms that are coupled to a corresponding one of the pair of jaws at the fulcrum region. Each of the pair of arms has an end opposite from the fulcrum region shaped for engagement with a slider. The jaws have an open position and a closed position, and the arms are disposed to cause movement of the jaws between the closed position and the open position when the arms experience displacement about the fulcrum region. Such displacement about the fulcrum region is effectuated by motion of the slider relative to the arms. The fastener assembly also has a second profile strip with a male element. The male element is captured by the female element when the jaws are in the closed position and released when the jaws are in the open position. A slider is longitudinally movable relative to the strips so as to cause the arms to experience displacement about the fulcrum region.
In accordance with another aspect of the invention the first profile strip has a rest position near a longitudinal end. One of the arms is truncated, so that when the slider is positioned at the rest position, the slider will not cause the arms to experience displacement about the fulcrum region and the jaws assume the closed position.
In still further embodiments of the invention, the slider has a leading end and a trailing end. (In the embodiments illustrated in the accompanying drawings, the xe2x80x9cleading endxe2x80x9d is the wide end of the slider and the xe2x80x9ctrailing endxe2x80x9d is the narrow end of the slider.) The slider also has a cross section that includes a first channel for capturing the ends of the arms and a second channel for capturing the end region of the male element. The channels experience a change in separation along a longitudinal axis, with the separation being greater at the leading end than at the trailing end. In this manner, motion of the slider in the direction of the trailing end pulls the end region of the male element away from the ends of the arms, while the jaws are in an open position, and the male element is pulled away from the female element. Additionally, the second channel may have an entrance and includes a restriction at the entrance near the leading end of the slider. The restriction limits angular motion of the tip of the male member and facilitates engagement of the tip with the first hook as the jaws assume a closed position.
In this embodiment, the slider cross section has a top and a bottom, and first and second channels may be disposed in the cross section so that they are vertically offset from one another. Additionally, the separation between the channels may remain constant in a second region near the trailing end of the slider, and the separation may increase progressively in a first region near the leading end of the slider, with the separation being relatively greater at the leading end. The first channel may also (or alternatively) decrease in width progressively in the second region (the width being relatively greater near the trailing end) and remain at a substantially constant width in the first region.
In accordance with another aspect of the invention, a method of removably fastening a first side panel to a second side panel is provided. The first side panel has a first profile strip that includes a female element having a pair of jaws, the jaws having an open position and a closed position and being actuatable by longitudinal motion of a slider, and the second side panel has a second profile strip that includes a male element. The method of this embodiment includes providing a slider longitudinally movable relative to the strips. A first longitudinal region of the slider is used to maintain the jaws in an open position while causing the male element to be displaced into the jaws, and a second longitudinal region of the slider is used to cause the jaws to move from an open position to a closed position. The slider is slid longitudinally along the strips so that the strips transition into a state wherein, along at least a portion of the strips, the male element is within the jaws and the jaws are closed.
In accordance with a further embodiment of the invention, a method for manufacturing a fastener assembly includes providing a first profile strip with a female element having a pair of arms, each of the arms having an distal end shaped for engagement with a slider. A second profile strip with a male element having an end region for engagement with the slider is also provided, as well as a slider that has a first side leg depending from one end of a top portion and a second side leg depending from an opposite end of the top portion. The end region of the male element is nullified for a length greater than the length of the slider, and a top arm of the female element is also nullified for a length greater than the length of the slider. A lower end of the first side leg of the slider is engaged with a bottom arm of the female element, and the top portion of the slider is rotated until the slider straddles the profile strips.
In a further embodiment, the method includes providing a first side panel and a second side panel, the first side panel depending from a lower jaw of the female element and the second side panel depending from the male element. After rotating the top portion of the slider, the slider is moved along the profiles to engage the uncut arms of the female profile and the end region of the male portion. The method also includes cutting through the profiles and panels to form components of a resealable enclosure.
In accordance with another embodiment of the present invention method for forming profile strips for a resealable closure includes extruding a molten material through a die. The die has an opening that approximates the shape of a desired profile. The molten material is drawn away from the die such that the molten material falls into a water bath. The molten material is then sized in the water bath. The molten material may be sized by a sizing device having a first portion for placing external bounds on the molten material and a second portion for preserving an interior space of the molten material.
In accordance with yet another embodiment of the present invention, a method for forming profile strips for a resealable closure includes extruding a molten material through a die having an opening that approximates the shape of a desired profile. The molten material is drawn away from the die and falls into a water bath. The water bath has a first region and a second region, the first region being controlled at a selected warmer temperature than the second region.